Meter for measuring electrical currents.



A. LOEWENBERG.

, METER FOR MEASURING ELECTRICAL CURRENTS. APPLICATION rum: MAR. 22, 1909.

1,020,565. Patented Mar. 19, 1912.

3 SHEETS-SHEET 1.

A. LOBWENBERG.

METER FOR MEASURING ELECTRICAL GURRENTS. APPLICATION FILED MAR. 22, 1909. 1,029,555, Patented Mar. 19,1912.

3 SHEETS-SHEET 2.

W/me 658$ Q 2.

lm/emo WLWL I A. LOEWENBERG.

METER FOR MEASURING ELECTRICAL CURRENTS. APPLIOATION FILED MAR 22, 1909.

1 0230 565,, Patented Mar. 19, 1912.

3 SHEETS*SHEET 3.

ALFRED LOEWENBERG,

PATENT OFFICE.

or o-nrcaeo, rLnxnors.

METER FOR MEASURINQ ELECTRICAL CURRENFIS.

Specification of Letters Patent;

Patented Mar. 1 a. 1 91 2.

Application filed March 22, 1909. Serial No. 484,846.

To all whom it may concern Be it known that I, ALFRED Lonwnnnnno,

- a citizen of the United States, residingat' Chicago, in the county of Cook and State 5 of-Illmois, have invented certain new and useful. Improvements 1n hleters for Measuring Electrical Currents, of which the following is a specification.

My invention relates to measuring instruments of the DArsonval type, where a coil moves in a permanent magnetic field. }A leading fault in these devices, as now cohstruoted, is in the number of joints in the assembled magnet, the pole shoes or fieldpieces being separated from the permanent magnet and joined thereto by screws or like means, a magnetic lag being caused wherever; a oint or screw s found. I overcome this' faultor defect by making the magnet" and'field pieces integral, whether solid or laminated, so that no joint or fastening screw exists between magnet proper and field-pieces. I also prefer to avoid the formation of holes or placing of screws in any part of magnet or field-pieces, to cause loss of magnetic force; all as will be understood from theensuing description and reference to the accompanying drawings,

in which latter 0 Figure 1 is a 'front elevation of a completed meter embodying one form of my invention, with dis. partly broken away and outer cap removed to expose the rela- .tions of the mechanism; Fig. 2, a horizontal 5 section through said meter on the correspondin ly numbered linein the preceding figure, s owing the magnet and field-pieces as laminated and illustrating the manner of mounting and centering the soft iron core between the field-pieces; Fig. 3, an alternative form of magnet and field-pieces,

l herein selected as the specific form. showing also the method of mounting the core therein and preventing-Jim poles from springing apart; Fig. '4, an end elevation of the oscillatory coil or movable element, with spiral hair springs and pointer or ini dicator; Fig. '5, a plan view of said coil, i showing the hair springs andthe inwardly projecting pivots to engage the jewels mounted axially intheends of the soft iron core, and also showing the pointer;

; Figs. 6 and. 7 respectii'ely, plan and ele- .vation of the nonmagnetic capwhich covlers core and coil and excludes dirt and iron dlTSt from them and from the field-pieces. EFig. 8, a front elevation of a completed meter built on the lines of thema et and accessories shown in Fig. 3,-and horizontal section through said latterme: ter on the line 88 of the foregoing figure.

Referrin now to said drawings, A, in

scribed as a double horse-shoe magnet, and A, in Figs. 3, 8 and 9, one of single horseshoe outline, each laminated integrally with its .insetting field-pieces, a, a, the whole thefieldieces and supported and'c'enteredi in the lie said field-pieces or magnets by tielat'es -D, D, but otherwise not penetrat-ive y attached to the latter by screws, bolts or the means for attachment of the instrumentto' the backboard X, and for supporting the -scale or dial (1, respectively as shown, and also, in the case of, integrally laminated magnets and field-pieces, for holding the laminations together. Non-magnetic caps E, are confined toplates D, D byscrews or in any other suitable manner, and completely cover.the ends of soft iron core and movable element, as well as the field-pieces, .to exclude detrimental matter from settling thereon or being drawn thereto. Both caps, but the. outer one especially, are capable of being taken 05 when it is desired pau'rposes or'for inspection and adjustment. rass screws 0 are, or may be, mounted in the keepers to take into the core and rigidly secure it. The double horse-shoe con struction insures the poles from springing and thus changing-thefield space and causing irregularity of action.

Instead of forming magnet and field-pieces in a single unitary block, the device may be formed of unitary laminated plates A A, the plates being laid parallel with the plane of the magnet. as indicated in the section displayed: in Fig. 2, the side elevation'bein of coursefthat shown-in Fig. 1, or that of laig 3, or any other suitable outline. Inthe form indicated in Fig. 3, being of single horseshoe outline, to avoid the possibility of the field space being changed by. springing of the poles, which is a source of irregularityin this' type of instruments, I employ suit- Figs. 1 an 2', represents what may be destructure being permanently magnetized,"

and B is a softiron core mounted between ds by keepers C KC) of b as -01:: other suitable diamagnetic material- 3in;- serted' or entered, as shown, betweenthe, field-pieces, and. held in place and against like, the tie-plates being secured tothe-exyfposed ends of the keepers and serving as ad.

to remove the core and coil for cleaningable means for locking the poles at a fixed distance apart, for instance I construct the duced cost and high c'oefiiciency. To further "economize in space and simplify examina tion of parts, I mount the jewels G axially in the ends of the core B, making one or both. of the jewels adjustable, as atg, and set the pivots H on coiLframe, or movable element, I to project inwardly and engage these jew els, thus supporting 0011 I and coil-frame upon and from the core with capacity of 0s: cilla'tion or vibration thereabout. This M'- rangcment permitsready reinovalof core and coil, with the coil in place upon the core and Swinging thereon, so that a close inspection may be had and perfect adjustment. be secured, and, in connection with theaforsaid non-metallic caps E, protects the parts from dust collecting, clogging or the moving ole;

' ment, and from iron chips which otherwise find their way to the fields, seriously inter: fering with the proper action of the insti'w ment and destroying its accuracy, This-peculiar assemblage of core and coil is obvi-- ous'lycapable of beneficial use with magnets and fields of other construction-than thespecific. type hereinabove described. Also the relative arrangement and position of coilframe pivots and supporting jewels is ntes sential to the action of the magnets and integral field-pieces of this novel type. Spiral springs K, like hair springs, fastened to the c0il-frame at their inner ends and to suitable nbutments, such as binding posts, at the outer ends, as in the Weston patent, 392,387 November 6, 1888, convey the current to the coil and act as a directing and controlling force thereto. The coil itself is wound on a metallic frame, preferably aluminum, to'ob-I tain a periodic or dead heat .eifect. The'; spaces L may reccive a suitable. resistance when'the instrument is used as agolt'meten.

Having thus'iiescribed my inventiomwhat- I claim and desire to secure by Letters Pat-1' ent of the United States is: j i y 1. The combination with" a permanent magnet having" insetting .fieldpieces, of :a soft iroii'cure moonted'alxinlly-between said field "pieces, brass keepers'supporting and center ng said core. tie .pla'tes holding said i keepers fromdisgla'cement, a back-board to Y which one of sai plates is attached, and, a current transmitting coil and coil frame.

pivotally connected with the core, axially 1 thereof:

2. -The combination with a 'permanent magnethaving insetting fieldieces integral therewith and allformed wit iout joints or perforations, of a soft iron core mounted axially between said field-pieces, an oscilla-- tor 'coil and coil frame hung upon said core, to oscillatethereon, brass keepers supporting and centering said core, and tie plates attached to the ends of said keepers to tie them together and prevent them from moving or springing apart.

3. The combinat on with a. permanent magnet having insetting field-pieces integral therewith and all formed of integral laminated platesyof a soft iron core mounted axially between said field-pieces, brass keepers supporting and centering said core, and tie plates'attach'ed to the ends of said keepers to hold the laminations togetherand prevent the kee ers from moving;

core, coil teafield; iecesr 5,-The cdr nbinat on with. a permanent magnet havin iiisftting'field-pieces integral t-hereivithan all formed of lritegral laminated plates, of a soft iron'cor'e mounted axially between said field-pieceskeepers supporting. and centering the core, tie plates binding the laminations together and holding: said keepers from 1noving,'a current transmitting coil .with coil -frame axially hung upon the core, and non-magnetic caps secured to said tie plates and covering and shielding the-core, coil and field-pieces.

6. A- ermanent :magnet with integral instting eldpieces provided with shoulders combined with ,a oke-clamped over sni shoulders to prevent springing or the fieldpieces, and means for clamping sa'id yoke in position; l

7. A'permanent magnet havin'g integral insett-ing ders, combined with a softironcore supported between said field pieces, brass keepers supporting-"and centering said core, means for tieing said keepers together, anda yoke attached to the 'outer keeper and clam ed over 1 the aforesaid shoulders there y., H v j p I I 'ALFRED Lonwnnnnne.

.VVitnesses: v

. MAX Gnniinnnnonn,

FRANK KnAnMmiL- tie plates iid 'covering and shielding the.

4. The combination with a permanent 

